Throughout the several decades of existence, video games have been littered with moments that keep gamers up at night. What defines these types of moments is the enemy experienced in each one. Whether the fear was invoked by implied terror or the site of horrifying characters, many video game enemies have tortured gamers. Here are five of the best video game enemies.

5. Mr. Bones (Roller Coaster Tycoon 2)

Some of the most frightening things are also the most innocuous — clowns, hallways, a skeleton with a top hat. Mr. Bones was simply a prop in Roller Coaster Tycoon 2 but he turned into the nightmarish caretaker of our worst selves and deepest hells.

“Mr. Bones Wild Ride,” a story made famous on 4chan, chronicled the tale of a user-made rollercoaster with a lengthy run-time of approximately three years. Every park visitor would be obliterated as excitement over the ride quickly turned into “I want to get off Mr. Bones Wild Ride.” The most devastating part came at the end, when riders were led back to the beginning, thus creating an infinite loop of eternal damnation.

There’s no earthly way of knowing… which direction we are going…

The story is hysterical, but the orchestration of this ride is nothing short of horrific. Monsters can exist in a game, but the scariest monsters are the ones that are ourselves as we view what horror can be wrought. Unlike removing the ladder from pools in The Sims, Mr. Bones is a physical incarnation of our disdain for anything we deem lesser than us. AI are just pawns in our sick games of magnifying glass versus ant.”

4. Snacker (Banjo-Kazooie)

Music can greatly heighten fear. A well-placed strike of a drum or the screech of a string instrument can turn a mild fright into a heart attack. That’s the case with Snacker the shark in Banjo-Kazooie.

From the look of a true predator on his face to the casual phrases he utters in relation to eating you, Snacker is a sociopath. His sole goal in life is to eat Banjo and Kazooie. But it is the tune that plays upon his appearance that creates a tense moment. Drawing obvious inspiration from Jaws, the tune has all the subtly of an axe murderer walking up the stairs in iron boots.

Snacker is one of the few truly terrifying things in a game that is otherwise overly cute. Thanks for the nightmares Rare, and further instilling the trope that “water is bad” in video games.

3. The Tank (Left 4 Dead)

Zombies capitalize on the innate human fear of death as well as the fear of monsters. Meanwhile, tanks instill a general sense of weakness. The tank in Left 4 Dead is a brutal monstrosity born of zombie mutation and serves as proof there is no God. While the other special infected in the Left 4 Dead universe can all be dispatched with a few well-placed bullets, the tank requires a concentrated effort from the four survivors, or at least a well-timed Molotov. His hulking size and demeanor are accompanied by a distinct shift in the game’s score as he lumbers toward the survivors.

Ha Ha Ha, oh HELLLL no.

Every good co-op shooter needs that one big enemy the team has to rally for in order to take down. The tank perfectly defines this role. Even if the team is fully loaded with the best gear and is topped off on health, the tank can single-handedly destroy everything. Coupled with the ferocity of his look, this is a recipe for the enemy of nightmares.

2. Alma (F.E.A.R.)

In F.E.A.R., players are given a variety of weaponry that allows them to eviscerate their enemies in a multitude of ways — except for Alma. Alma is partly an antagonist and partly a victim. Experimentation and torture made her into a seriously disturbed apparition, but having her children stolen from her really put her over the edge.

Alma mostly appears in cutscenes, but a number of in-game moments allow the player to fire at her to no avail. The sole exception is F.E.A.R.’s climax, in which players move to uncover the truth behind Alma. She appears every few seconds as she slowly approaches the player. If she isn’t shot, she will instantly kill them.

Alma is incredibly creepy, but what earns her a place on this list is seeming omnipresence. Wherever players go she is there, ready to turn a hall red with blood, kill some random military types or just watch you. Alma puts the fear in F.E.A.R. by always keeping players on their toes, never sure when she will next be waiting.

1. The Clowns (Clown House)

Despite their attempts to bring joy, most people will agree that clowns are creepy. Several games have attempted to recreate this fear, but Clown House has one major difference: the clowns are you.

This free game on Steam takes all of five minutes to complete. You enter the house, shoot the key (to grab it) and get the hell out. But there are three clowns in the house, and they are either neutral or murderers. Neutral clowns merely wallow and watch, but murderers become crazed at random. Luckily, you are equipped with a gun, but shooting every clown you see can bring on a fate worse than death. If you kill a neutral clown, you become one. The implication is that these clowns were once others that had to escape this house and instead of trying their luck, shot the first clown they saw as well.

I never asked for this.

Keeping your distance and waiting for the music to begin isn’t challenging, but the horror of waiting and wondering will shake any player’s nerves. And just in case you don’t know to be scared, the game’s music is meant purely to startle players.